CSS3 has some new values for sizing things relative to the current viewport size: vw, vh, and vmin. It is relevant to bring up now, because it's shipping in Chrome 20 (canary at the time of this writing). And not behind a flag, it just works. via Pocket

Yes, Chris wrote this in 2012, but I'm just now finding time to play with it. The `vw` and `vh` sizing meaurements in CSS allow elements to size based on viewport dimensions. Played with it a bit and it's really cool in Chrome and Safari. I should probably start testing stuff in Firefox again...